This invention relates to a starter device for an internal combustion engine, and, more particularly, it is concerned with a starter device of a recoil type for use in a small sized internal combustion gasoline engine mounted on a motor-cycle and the like.
This type of starter device for the internal combustion engine has been of such a construction that an engine starting rope or cord which is wound on a pulley by force of a spiral spring is vigorously pulled out so as to cause the rope pulley to perform a single turn, and the rotational force of this rope pulley is transmitted to a starting pulley through a forwarding pawl to thereby rotate the crank shaft of the engine fixedly secured on the rope pulley.
The abovementioned forwarding pawl becomes engaged with the starting pulley, only when the engine is started, and is automatically disengaged from the starting pulley after the engine starts so as to reinstate itself to its state prior to the engine start.
In the heretofore known starter device, since a cam plate or a ratchet mechanism or the like has been used for an engaging and disengaging mechanism with respect to the starter pulley for the abovementioned forwarding pawl, the construction of the device is complicated.
In view of the disadvantages inherent in the known type of the engine starter device, it is the primary object of the present invention to provide an improved starter device for an internal combustion engine which has successfully solved the abovementioned problems, is simple in construction, is adapted for industrial mass-production, is accurate in its operation, and is cheap in its manufacturing cost.
According to the present invention, generally stated, there is provided a recoil type starter device for an internal combustion engine which comprises: a casing; a starting pulley which is fixed at one end of an engine crank shaft within the casing, and has at least one opening in the circumferential side surface thereof; a rope pulley which is provided in confrontation to the starting pulley, and is supported in a rotatable manner on a separate fixed shaft within the casing; a forwarding pawl having a pawl portion at one end thereof to be engaged with the perforated opening of the abovementioned starting pulley and a spring fitting portion at the other end thereof, and which is oscillatably supported on a shaft in a on the side surface of the rope pulley to transmit the forward rotational force of the rope pulley in engagement with the opening of the starting pulley to start the engine; a spiral spring to take up the starting rope around the periphery of the rope pulley after start of the engine by reversely rotating the rope pulley; a stationary disc which is mounted on the supporting shaft of the abovementioned rope pulley; a wire spring part of which is in the shape of a letter "U", with two legs, an outer end of one of which is connected to the spring fitting part of the abovementioned forwarding pawl, and an extension of the end of the other of which frictionally embraces the circumference of the abovementioned stationary disc, being wound therearound in substantially a single turn, the wire spring having a force which tends to cause the two legs thereof to open outwardly to a position to cause the forwarding pawl normally to be retracted. The spring acts as a drag link between the forwarding pawl and the stationary disc when the rope pulley is rotated relative to the disc in a starting direction so as to erect the forwarding pawl. A stop is provided on the side surface of the rope pulley to limit the angle of erection of the abovementioned forwarding pawl and to cause the forwarding pawl to be engaged with the perforated opening of the starting pulley; and a projected member is provided on the side surface of the rope pulley to contact with a tail of the part of the wire spring frictionally contacted around the stationary disc, when the forwarding pawl becomes engaged with the starting pulley to reduce the frictional contact force of the wire spring with respect to the stationary disc.
There has thus been outlined rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter. Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is important therefore that the claims be regarded as including such equivalent constructions to an extend that they do not depart from the spirit and scope of the invention.